Recently, various portable storage mediums have been introduced as a result of a constant change in a network environment and a demand for a more convenient data storage and improved mobility. Further, new storage mediums lead to the development of high capacity portable storage devices using a flash memory.
Such portable storage devices that have been purchased by certain experts are now used as essential peripheral devices of a personal computer (PC), e.g., a bundled product provided with a purchase of a PC, or those of a personal digital assistant (PDA), e.g., accessories of a PDA.
Accordingly, a market size of the portable storage devices will be gradually expanded. The portable storage devices have been used mainly by professionals, e.g., graphic designers who often transmit high capacity data. However, as data capacity of a multimedia file such as game software and MP3 files becomes large, purchases by non-professionals are on the rise.
Especially, since Intel Corp. and Microsoft Corp. announced their plans not to support a floppy disc drive (FDD), a portable storage device is expected to replace the FDD. Further, the portable storage device is suitable for an auxiliary storage device of a PDA having a small storage capacity. Therefore, an increasing demand for the portable storage device of PDA manufacturers is also predicted.
Major features of the portable storage device are its remarkable portability, mobility, compactness, and lightness. Moreover, the portable storage device can be simply connected without a separate adapter and does not require a separate power supply due to enough power provided from a USB port.
Meanwhile, the portable storage device having the above-described advantages has been developed based on an USB. technology. The USB is a peripheral bus protocol developed by Compaq Corp., Intel Corp., Microsoft Corp., and the like for the initial purpose of providing a simple method for integrating a computer and a telephone.
Such protocol has been developed into a USB 1.0 standard for facilitating a convenient integration of maximum 127 peripheral devices in a PC. And also, a USB 1.1 standard complements problems of the USB 1.0 standard. Such USB technology is able to support new devices capable of transmitting voice data and compressed video data in real-time, synchronizing mixed modes, varying PC components, and improving PC performance.
In the meantime, the USB, which is basically a serial bus, implements a notion of master/slave and provides a direct connection or a connection through a hub between a host and each peripheral device.
Currently, various products employing a USB interface are introduced, wherein the USB interface allows a connection between a PC and most of peripheral devices, e.g., a printer, a scanner, a keyboard, a mouse, a joystick, a gamepad, a video camera, a still image camera, a modem, an ISDN adaptor, and an ethernet adaptor.
Further, connectors, e.g., USB to IDE, USB to PS/2, USB to printer port, USB to serial port, and the like, can be used for connecting conventionally used devices with a USB port.
FIG. 1 shows a conventional portable storage device having a USB port at one side thereof.
As illustrated in FIG. 1, the conventional portable storage device has a structure of an inner main body being completely covered by a case 1. The inner main body includes therein memories (ROM and RAM), a clock signal generator, an interrupt controller (not shown), and the like, thereby enabling data to be downloaded from peripheral devices through a USB port 3 and data stored in the memories to be uploaded to a PC, PDA and the like.
Meanwhile, the portable storage device is provided with a sheath 2 for protecting the USB port 3 functioning as a main input/output unit of memories from external damages and a user from the USB port 3 made of sharp materials. Since, however, the sheath 2 is separable from the case 1, it is inconvenient to carry. Further, in case the sheath 2 is lost, it is hardly possible to protect the USB port 3. In addition, with a possibility of causing physical injuries to the user, the portable storage device is not convenient to use and carry with the sheath 2 off.